1. Technical Field of the Invention
This invention relates to radio telecommunication systems and, more particularly, to a system a method of preventing fraudulent call transfers by disabling a mobile telephone's immediate call transfer feature when certain conditions are met.
2. Description of Related Art
Existing radio telecommunications networks offer a subscriber several call-transfer features. Such features may include, for example, Transfer-on-Busy (TRB), Transfer-on-No-Answer (TRN), and Call Transfer Immediate (CTR). When utilizing the CTR feature, a subscriber programs a forward-to number into the home location register (HLR) associated with his mobile telephone. Thereafter, calls to the subscriber's SNB (subscriber number) are immediately transferred to the programed transfer-to number, regardless of the status of the subscriber's mobile telephone.
While the CTR feature may be a convenience for many subscribers, it also poses a threat of fraudulent use. Typically, a fraudulent user clones the legitimate subscriber's mobile telephone, including the electronic serial number (ESN) and mobile identification number (MIN). Thereafter, the cloned telephone appears to the network to be the subscriber's legitimate telephone. The fraudulent user then utilizes the CTR feature to sell long distance service to other fraudulent users. This can be done in the following manner:
(1) Fraudulent User No. 1 (in City A) clones the mobile telephone of a legitimate subscriber who subscribes to the CTR feature; PA1 (2) Fraudulent User No. 2, who is in the local calling area of Fraudulent User No. 1, wants to call a long distance telephone number in City B; PA1 (3) Fraudulent User No. 1 programs the telephone number in City B as the forward-to number for the CTR feature in the local HLR; PA1 (4) Fraudulent User No. 2 then makes a local call to Fraudulent User No. 1 using the SNB of the cloned mobile telephone; PA1 (5) Since the CTR feature is activated, the call is immediately forwarded to the long distance number in City B, and the legitimate subscriber is billed for the long distance charges; and PA1 (6) Fraudulent User No. 1 may then program another long distance telephone number as the forward-to number for the CTR feature in the local HLR, and sell the long distance service to mother fraudulent user. Once again, the legitimate subscriber is billed for the long distance charges.
There are no known prior teachings of a solution to the aforementioned deficiency and shortcoming such as that disclosed herein.
In order to overcome the disadvantage of existing solutions, it would be advantageous to have a system and method of preventing fraudulent call transfers by disabling a mobile telephone's immediate call transfer feature when certain conditions are met. The present intention provides such a system and method.